Provisionals: not a stopgap but the instrument that decides the shape of the tissue

The provisional is still regarded as a stopgap for the waiting period. It is instead the instrument that determines the shape the soft tissue will have when the definitive arrives — and by then the shape is already decided.

There are four functions, none of them secondary: protecting exposed dentine, maintaining the position of the element, guiding tissue healing, and allowing the patient to assess aesthetics and phonetics before everything becomes irreversible.

The third is the most neglected. Gingival tissue adapts to the shape it contacts, and after a few weeks that shape is stable: a provisional with a wrong emergence profile produces a gingiva the definitive will have to accept.

The direct technique with self-curing acrylic resin is quick and inexpensive, but has two real limitations. The reaction is exothermic, with temperatures that can exceed 60 degrees on exposed dentine, and polymerisation shrinkage worsens marginal adaptation.

Both problems are reduced by removing the matrix before complete polymerisation and finishing the set out of the mouth in warm water. It is a step costing thirty seconds, and one often skipped when working in haste.

Bis-acrylic materials have resolved much of this: less exotherm, reduced shrinkage, superior polishability. The unit cost is higher but finishing time is markedly shorter, and the overall account balances.

The indirect technique, with the provisional made in the laboratory on a model, remains the reference in complex cases: extensive rehabilitations, increases in vertical dimension, cases where the provisional will remain in the mouth for months.

Laboratory acrylic resin, heat and pressure cured, has far superior mechanical properties to the self-curing type: it absorbs less water, discolours less and withstands prolonged function without fracturing.

Polishing is what separates a functional provisional from a harmful one. A rough surface accumulates plaque within days, and the resulting inflammation alters the tissue precisely where stability is needed.

Margin finishing deserves the same time one would give a definitive. A provisional with subgingival excess produces chronic inflammation; one that is short leaves dentine exposed and sensitive.

Emergence profile conditioning is the technique distinguishing an ordinary provisional from one that works. Adding or removing resin at precise points guides the papilla and shapes the gingival contour during the waiting weeks.

The profile thus achieved must then be transferred to the laboratory: an impression of the provisional, or a scan, communicates the shape reached. Without that step the definitive is made on a theoretical form and the conditioned tissue is lost.

In summary, the provisional should be treated as a dress rehearsal, not a makeshift. The time spent finishing and polishing it is fully recovered at delivery, when the tissue is where it should be.